The question is, when such market transaction costs come into play. I don't think that they are so high to justify not taking different salaries into account wo

The question is, when such market transaction costs come into play. I don't think that they are so high to justify not taking different salaries into account world-wide. Besides, determining the median salary might also be not very accurate without research. But at least for my country, differences between the salary for software engineering per region are quite transparent. They would not exist in the first place, if they were really so hard to determine, at least roughly.